aiochclient 0.0.1

Async http clickhouse client for python 3.6+

aiochclient

Async http(s) clickhouse client for python 3.6+ with types converting and streaming support

Quick start

aiochclient needs aiohttp.ClientSession for connecting:

from aiochclient import ChClient
from aiohttp import ClientSession


async def main():
    async with ClientSession() as s:
        client = ChClient(s)
        assert await client.is_alive()  # returns True if connection is Ok

Query example:

await client.execute("CREATE TABLE t (a UInt8, b Tuple(Date, Nullable(Float32))) ENGINE = Memory")
await client.execute("INSERT INTO t VALUES (1, ('2018-09-07', NULL)),(2, ('2018-09-08', 3.14))")

Rows fetching:

For fetching all rows at once use fetch method:

all_rows = await client.fetch("SELECT * FROM t")

For fetching first row from result use fetchone method:

assert (await client.fetchone("SELECT * FROM t WHERE a=1")) == (1, (dt.date(2018, 9, 7), None))

You can also use fetchval method, which returns first value of the first row from query result:

assert await client.fetchval("EXISTS TABLE t")

Async iteration on query results steam:

async for row in client.cursor(
    "SELECT number, number*2 FROM system.numbers LIMIT 10000"
):
    assert row[0] * 2 == row[1]

ChClient returns rows as tuples.

Types converting

aiochclient automatically converts values to needed type from Clickhouse response.

Clickhouse type	Python type
UInt8	int
UInt16	int
UInt32	int
UInt64	int
Int8	int
Int16	int
Int32	int
Int64	int
Float32	float
Float64	float
String	str
FixedString	str
Enum8	str
Enum16	str
Date	dt.date
DateTime	da.datetime
Tuple(T1, T2, ...)	tuple(T1, T2, ...)
Array(T)	list(T)
Nullable(T)	None or T
Nothing	None

Connection pool size

If you use aiochclient in web apps, you can limit connection pool size with aiohttp.TCPConnector.